Some newer vehicles are configured to enter a welcome mode upon detecting an approaching driver. In response, the vehicles typically perform one or more welcome mode functions (e.g., activating puddle lights, unlocking doors, etc.). The vehicles typically detect an approaching driver by receiving a wireless transmission, at a single location, from a key fob. Such a technique, however, does not enable the vehicle to accurately determine a location, velocity, or acceleration of the driver with respect to the vehicle. Thus, the vehicle may incorrectly activate welcome mode when the driver is passing near the vehicle, but not walking toward the vehicle. As a result, the vehicle may waste energy and inappropriately unlock.